docs: def build_filename(filename, filetype='png', resolution=300):
      """
      Uses the input properties to create the string of the filename
  
      :param str filename:
          Name of the file
      :param str filetype:
          Type of file
      :param int resolution:
          DPI resolution of the output figure
      """
      filevals = os.path.splitext(filename)
      if filevals[1]:
          filetype = filevals[1][1:]
      if not filetype:
          filetype = 'png'
      filename = filevals[0] + '.' + filetype
  
      if not resolution:
          resolution = 300
      return filename, filetype, resolution